The present invention relates to constitution of a magnetic recording and reproducing apparatus (hereinafter referred to as a magnetic recording/reproducing apparatus) equipped with a tape-running control unit which controls the running of the tape when the-data are recorded onto or reproduced from the tape or when access is made to the data recorded on the tape in order to reproduce the data or to record the data.
When access is made to a predetermined data block in a conventional magnetic recording/reproducing apparatus, the position of a data block just before the predetermined data block is read out in order to detect the heading of the position of the data block, the tape is halted until the data to be recorded are transferred, and recording means for recording the data is maintained under stand-by condition. In this case, the cylinder mounting the recording or reproducing head continues to rotate, so that the head scans a portion of the tape on which the data are recorded.
According to the thus constituted conventional art, the stand-by condition is established when press-contact of the pinch roller with the capstan is released to separate the tape away from the capstan, and at the same time a braking force is applied to a reel plate. Therefore, when there is used a brush motor for driving the mode member, the brush is worn out at an early time to reduce the life of the motor. Further, wear in the bearing of rotary support of the pinch roller causes the pinch roller to be deviated and the mechanism to be deteriorated. The bearing of the rotary support of a brake member is worn out, too. Moreover, when the tape is at rest under the stand-by condition, the head scans repeatedly the portion of the tape where the data are recorded. Therefore, data tends to be dropped out and the S/N ratio tends to decrease resulting in the loss of reliability. In the conventional art, furthermore, no countermeasure has been made to improve the reliability and life of the mechanism during the repositioning operation of the tape, to improve the reliability of the data recorded on the tape, or to preventing the tape from being damaged.